Fluid pump or motor having rollers

ABSTRACT

An inner member and an outer member are relatively rotatable, and the members are arranged with fluid passageways, and the members define an annular chamber or working space. One of the members has rollers rotatably mounted to extend into the annular space, and the other of the members has vanes fixed thereto and extending into the annular space. The rollers have pockets for receiving the vanes when the rollers roll over the vanes. The roller pocket surfaces and the vanes are formed to provide rotation timing as the rollers pass over the vanes so that relative rotation of the two members is maintained the same as it is when the vanes are not in the roller pockets.

United States Patent Inventors Philip Hartmann Racine; Jack E. Lake, Sturtevant, Wis. 826,505

May 21, 1969 Apr. 13, 1971 Koehring Company Milwaukee, Wis.

Appl. No. Filed Patented Assignee FLUID PUMP OR MOTOR HAVING ROLLERS 126 (TR);230/l50; 123/13 (B);91/8l,92; 418/150, 189,190,191,l96;4l8/l12,119, 161,

References Cited UNITED STATES PATENTS 152,904 7/1874 Greindl 103/125 Primary ExaminerCarlton R. Croyle Assistant Examiner.lohn J Vrablik Attorney-Arthur .l. l-lansmann ABSTRACT: An inner member and an outer member are relatively rotatable, and the members are arranged with fluid passageways, and the members define an annular chamber or working space. One of the members has rollers rotatably mounted to extend into the annular space, and the other of the members has vanes fixed thereto and extending into the annular space. The rollers have pockets for receiving the vanes when the rollers roll over the vanes. The roller pocket surfaces and the vanes are formed to provide rotation timing as the rollers pass over the vanes so that relative rotation of the two members is maintained the same as it is when the vanes are not in the roller pockets.

PATENTEU APRLBIENI 3574.490

INVENTORS V J. 5. K5 r1 :5. a a

'77'ORNEV F. hMRTMANN FLUID PUMP OR MOTOR HAVING ROLLERS This invention relates to a fluid pump or motor having rollers. When used as a pump, the apparatus has one of two relatively rotatable members driven by an outside power source. The members have fluid passageways for the inlet and outlet of hydraulic fluid which is displaced by the driven member of the pump, as desired. When the apparatus is used as a motor, then fluid is admitted into the apparatus under pressure and provides the driving force for the rotatable member.

BACK GROUND OF THE INVENTION Fluid pumps and motors are well-known in the art. The particular type of structure or device involved in this invention is that which employs rollers to serve as abutments for blocking and controlling the flow of fluid within the device. The use of rollers in fluid pumps or motors is not new. For instance, US. Pat. No. 3,264,944 shows a fluid pump or motor having two relatively rotatable members, and one of the members has rollers rotatable therein, and the other of the members has vanes extending into the path of the rollers so that between the rollers and the vanes, the fluid is active and effective in inducing the relative rotation desired.

The concern with all hydrostatic or fluid apparatus is the fluid sealing of the apparatus at locations between its moving parts. Of course if there is incomplete fluid sealing, and fluid leakage results, then the apparatus is inefficient. Of course it is essential that adequate fluid sealing be accomplished with a reasonably sturdy, long wearing, easily manufactured, high speed, adequate capacity, and like characteristics of the apparatus.

Another concern with the roller-type of fluid pump or motor apparatus is that there be uniform relative rotation between the two relatively rotatable members, even when the roller is passing over the vane of the other member. Without accomplishing uniformity in the relative rotation as mentioned, there would of course be one speed of rotation when the rollers are clear of the vanes and there would then be another speed of rotation when the rollers are passing over the vanes. This would provide for undesirable results, including jerky or nonuniform speed of rotation throughout the complete cycle of each revolution of the rotating member, unless special timing teeth are used.

Still further, it is desirable to provide the roller-type of fluid pump or motor apparatus in an arrangement whereby the rollers are not unduly loaded or forced upon by the working fluid. Any undue force on the roller will create manufacturing problems as well as creating unnecessary wear on the parts, and ultimately the parts will fail to serve their primary function of fluid sealing in that the parts will permit leakage of the fluid.

Still another concern with regard to the roller-type of fluid pump or motor is that there should be no backlash between the moving parts. That is, when one of the members is rotating in one direction relative to the other member, the other member should not have any freedom to rotate relative to the first member in that same direction. This is the common concern of backlash between rotating parts, such as gears. In the present invention, gear teeth are employed for fluid sealing and rotation timing, and when the roller pockets receive other vanes of the other member, there should be no backlash in the rotative motion of the two members.

Additionally, in the roller-type of fluid pump or motor, it is of concern that the vane over which the roller rotates is a sufficiently sturdy vane to receive considerable force exerted by high-pressure fluid, Likewise, it is important that the roller be arranged to have its gear teeth and the like sufficiently sturdy to withstand the mechanical and hydrostatic forces acting upon it. Therefore, it is important and significant that the apparatus be arranged to withstand the large forces while the apparatus is also arranged to accomplish the aforementioned objectives.

Still further, the concern of the prior art is with the provision of a roller-type of fluid pump or motor which has only a minimum of bearing load on the rollers, and which can eliminate any rotation-timing teeth operative between the rollers and the other member, and with the members being reversible in their direction of relative rotation. Thus, where US. Pat. No. 3,264,944 has short length of gear teeth on the rollers, as shown on the top of FIG. 1 where the short roller teeth are flanking the ends of the vane, the present invention does not require any such additional length of gear teeth for rotation timing between the rollers and the other member. This therefore eliminates a certain length of the roller at the location where it is subjected to high pressure fluid, and this therefore minimizes the bearing load on the roller. Nevertheless, the present invention does not require timing teeth, such as those shown in US. Pat. No. 2,690,164, and instead, contrary to the showing in FIG. 6 of the latter said patent, the present invention achieves rotation timing by having the roller in contact with the vane throughout the movement of the roller over the vane on the other member.

SUMMARY OF THE INVENTION This invention has two relatively rotatable members, one of which has rotatable rollers, and the other of which has vanes. The two members define an annular space therebetween, and the vanes are disposed within the space. The rollers have pockets for receiving the vanes, and the rollers and the member with the vanes have fluid-sealing gear teeth therebetween for fluid sealing and rotation timing. The roller pockets and the vanes are specially shaped to be in contact throughout the time the vanes are received in the pockets, and the special shape is such that the relative rotative speed between the members when the gear teeth are in mesh is the same when the vane is received by the roller pocket so that uniform and constant rotation can be maintained.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a plan view of fragments of the two members of the preferred embodiment of this invention.

FIG. 2 is an enlarged axial and fragmentary view of the parts shown in FIG. 1.

FIG. 3 is a perspective view of the parts shown in FIG. 2, but in a slightly different position.

FIG. 4 is an enlarged axial view of a fragment of the rollers shown in the other views.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The US. Pat. No. 3,264,944 shows the overall fluid pump or motor to which this present invention pertains. The present invention shows how the patented pump or motor is changed to accomplish the desired objectives mentioned in the aforegoing. Thus, the present drawings show two relatively rotatable members 10 and 11. An annular space or working chamber 12 is defined by these two members, and FIG. 1 shows the axial length of the annular space while FIG. 2 shows the circular wall 13 which defines the outer surface limiting the annular space 12. Member 10 has a plurality of circular bores 14, and these bores open into the annular space 12, and they do so by a dimension shown in FIG. 2. The other member 11 has vanes 16 which have their end surfaces 20 in fluidsealing relation with the circular wall 13. Also, there are two vanes I6 and 17 which are spaced apart so that their maximum spacing between their outer surfaces 20 present the dimension D. The dimension D is greater than the dimension d so that the two vanes I6 and I7 span the bore l4 when the members I0 and I I are in position with the bore I4 between the vanes l6 and I7, and such position would be when the member 10 is relatively rotated in the direction of the arrow A and beyond the position shown in FIG. 2.

The member I0 therefore has a plurality of bores I4 spaced therearound, and a roller 18 is snugly received in each of the bores 14. The roller 18 has a centerpiece which includes the two cylindrical portions 19 and the gear teeth 21. Each of the two portions 19 has sleeves 22 snugly disposed thereover, and the sleeves tenninate in rims 23 which are immediately adjacent the ends of the teeth 21 and are of a diameter equal to the outer diameter of the teeth 21, as shown. Thus the rollers 18 are snugly but freely rotatable in the member 10.

The member 11 also has two cylindrical ends 24 which are available for mounting the member 11 in the apparatus shown, and the member 11 has gear teeth 26 which mesh with the roller gear teeth 21. The gear teeth 21 and 26 are in fluidsealing relation, and they create a selected or given rotational relationship between the members and 11. Of course the vanes 16 and 17 interrupt the teeth 26, but the vanes are of a thickness across their base to be related to the thickness of the teeth so that the rollers 18 move over the vanes 16 and subsequently l7 and the gear teeth 21 and 26 mesh on both sides of both vanes 16 and 17. Thus the rollers 18 have web portions 27 which extend between the vanes 16 and 17 as shown by the roller 18' in the dot-dash lines in FIG. 2 which indicates a new position .for the roller 18 when rotation occurs in the direction of the arrow A. Also, rollers 18 have two pockets 28 which respectively receive the vanes 16 and 17 as the roller relatively moves as mentioned. The particular relationship between the vanes 16 and 17 and the roller pockets 28 will be mentioned later.

Fluid passageways 29 and 31 are shown in FIGS. 1 and 2 and 3, and these are available for inlet and outlet of fluid, depending upon the use of the apparatus as a pump or motor and depending upon the direction of rotation desired between the members 10 and 11. When it is desired to move the member 10 in the direction of the arrow A, then passageway 29 would be an inlet for high-pressure fluid, and passageway 31 would be the outlet. Such arrangement would cause fluid pressure to act on the rollers 18 which are spaced around the annular chamber 12, so rotation in the direction of arrow A would occur. Of course the vanes 16 and 17 prevent fluid from flowing directly from the inlet 29 and into the outlet 31. This is also true when the bore 14 is disposed between the vanes 16 and 17, since the dimension D is greater than the bore opening 4, and rollers 18 fluid seal in bores 14.

An important feature is to have the members 10 and 11 rotate at the same relative speeds when the vanes 16 and 117 are received in the pockets 28, as when they are not so received. That is, the gear teeth 21 and 26 provide a certain relative rotation between the members 10 and 11, and it is desirable to retain that rotative relationship and have it uniform even when the vanes 16 and 17 are in either or both of the pockets 28. To do this, the surfaces in the rollers 18 and defining the pockets 28 are formed to be a continuation of the curved shape of the teeth 21 on the side adjacent the pockets 28. That is, FIG. 4 shows the tooth 21 being of an involute shape and having a pitch circle along the line 32. The teeth 21 and 26 normally are considered to be in mesh on the pitch circle. Also, the teeth have a root circle indicated by the line 33, and the circles 32 and 33 define the addendum and dedendum of the teeth 21. The pockets 28 are defined by the surfaces 34 which are the continuation of the dedendum tooth surface, and the surfaces 34 extend radially within the root circle 33. The surface 34 is shown to be an are generated about the radius R, and the surface 34 extends for an angle designated B which is shown to be defined by the root circle and the dotdash line at the opposite end of the angle B, and this angle is shown to be approximately 50. The pocket 28 then continues from the surface 34 and beyond the line designated 36 and into the surface designated 37 which extends around to the opposite side of the pocket 28 and to the surface 34 on that opposite side. Thus, as seen in FIG. 2, the pockets 28 have two adjacent teeth 21 which flank the pockets 28. Also, the teeth 21 have their outer end surfaces 38 in fluid-sealing and snug contact with the circular walls defining the roller bores 14. The teeth 26 have similar end surfaces 39. and the faces of each of the vanes 16 and 17 are formed in the same arcuate shape as the faces of the teeth 26, so that the lines 41 in FIG. 3 indicate the position that the tooth surfaces 39 would be in if the teeth 26 were continued around the member 11 in the location of the vanes 16 and 17. That is, the roller teeth 21 mesh with and relate to the vanes 16 and 17 at the face of the vanes 16 and 17 in he same manner that they relate to the teeth 26, since these faces are of the same involute shape as that of the teeth 26.

With the roller pockets formed by the arcuate surfaces 34, and with the arcs 34 being generated at the base of the teeth 21, and the radius R being centered on the root circle 33, the vane opposite faces 42 and 43 are generated or developed by rolling the roller 18 over the vanes 16 and 17 to have an epicycloidal pattern developed and thereby establish the faces 42 and 43. In this arrangement, the vanes 16 and 17 are in constant contact with the roller surfaces 44 defined by the arcs 34, as shown between the two dot-dash lines in FIG; 3. The surfaces 44 actually slide and also roll over the vane surfaces 42 and 43 so that there is snug and constant contact when the roller 18 moves over the vanes 16 and 17. This provides for the rotation timing desired between the members 10 and 11, and it does not require the extended teeth on the rollers 18, nor does it require special timing teeth between the members 10 and 11. Therefore, the axial length of the annular space 12, as seen in FIG. 1, is the same as the complete length of the teeth 21 and 26, as shown in FIG. 1, so there is less bearing load on the rollers 18, and there is less precision required in making the apparatus, as compared to US. Pat. No. 3,264,944. The surfaces defining the pockets 28 and being adjacent the roller teeth 21 are therefore curved surfaces, and the vane faces 42 and 43 are also curved and are developed and generated by the mechanical process mentioned.

To relieve any fluid that would be present between the vanes 16 and 17, the rollers 18 are provided with fluid-relief passageways 46. Also, relief-fluid passageways 47 are formed in member 11 and extend between the vanes 16 and 17 and are actually aligned and therefore in flow communication with the passageways 46 to permit fluid to pass from between the vanes 16 and 17 and to the outside thereof in the direction opposite that of the direction of rotation shown by arrow A, for instance.

Of course it will also be understood that the length of the vanes 16 and 17, as defined by the line 48, is substantially the same as the axial length of the annular space 12 so that the vanes 16 and 17 are fluid tight with the sidewalls 49 and 51 in the member 10 and defining the sides of the annular chamber 12. Also, the vanes 16 and 17 have the end surfaces 20 with the dimension defined by the line 52 considered in conjunction with the line 48.

With the arrangement of the surfaces 44 as described, the roller teeth 21 adjacent the pockets 28 are sufficiently strong to withstand fluid and mechanical pressures, and the span of the are 34 is of a length so that some portion of the are 34 is in rolling or sliding contact with the surfaces 42 or 43 on the vanes 16 and 17, and this requires an angle B of at least approximately 30. Also, the surfaces 42 and 43 continuous curvilinear surfaces extending beyond the tooth crowns defined by the lines 41 in FIG. 3.

Just as in US. Pat. No. 3,264,944, the two vanes 16 and 17 act as a single vane to span the roller bores 14 and preclude fluid from passing between the inlets and the outlets except after performing the required work. Also, there are twice the number of rollers 18 as there are pairs of vanes 16 and 17, so that the unit, as in said patent, is similar thereto.

We claim:

1. In a fluid pump or motor of the type including an inner member and an outer member and an annular space between said members, said members being relatively rotatably related, one of said members having bores therein contiguous to and spaced along said annular space, rollers rotatably mounted in said bores and extending therefrom through said annular space, said rollers and the other of said members having gear teeth in fluid-sealing meshing relation across the axial length of said annular space, vanes extending radially on said other of said members in spaced relation therearound and with each of said vanes having two oppositely disposed faces extending through said annular space and with each of said vanes having a radially outwardly disposed end surface in fluid-sealing relation with said one of said members, said rollers having a pocket interrupting said gear teeth on said rollers for receiving said vanes during the relative rotation of said members, said other of said members having a fluid inlet and a fluid outlet for the passage of fluid relative to said annular space, the improvement comprising two of said gear teeth on said roller being disposed adjacent said pocket for defining limits to said pocket, two convex arcuate surfaces on said roller and extending continuously radially inwardly from said two gear teeth for further defining limits to said pocket at opposite sides of said pocket, said two opposite faces of said vane being curvilinearly shaped and generated in conformance with rolling said roller over said vane and having said two convex arcuate surfaces simultaneously disposed on respective epicycloidal curves defining the entire vane curvilinearlyshaped faces, for rotation timing between said members when said vane is in said pocket so that relative rotation between said members is identical when said vane is in said pocket compared to when said gear teeth are in mesh.

2. The subject matter of claim 1, wherein said gear teeth on said roller and one said other of said members are of a length equal to the axial length of said annular space.

3. The subject matter of claim 1, wherein said gear teeth on said roller have a root circle along the radially inwardly disposed base of said gear teeth on said roller, and said two convex arcuate surfaces being located to have their respective centers on said root circle.

4. The subject matter of claim 3, wherein the radius of the arcuate shape of each of said convex arcuate surfaces is equal to the width of said gear teeth along said root circle.

5. The subject matter of claim 4, wherein the arc of each of said arcuate surfaces spans an angle of at least 30.

6. The subject matter of claim 1, wherein said roller has a fluid relief passageway in the surface defining said pocket and being spaced from said two gear teeth, for the relief of fluid pressure on said two opposite faces of said vane when said vane is in said pocket.

7. The subject matter of claim 1, wherein said bores open onto said annular space with a dimension along said annular space less than the diameter of said roller, the spacing between two immediately adjacent ones of said vanes being such that the longest distance between said end surfaces of said vanes is greater than said dimension of said bores, to have two of said end surfaces respectively simultaneously disposed on opposite sides of said bores for fluid sealing with said one member across said bores, and each of said rollers having two spaced apart pockets for respectively receiving said vanes upon relative rotation of said members.

8. The subject matter of claim 7, wherein said gear teeth between said two immediately adjacent said vanes have a fluid relief passageway extending across said gear teeth and into said two vanes for the relief of fluid pressure between said two vanes. 

1. In a fluid pump or motor of the type including an inner member and an outer member and an annular space between said members, said members being relatively rotatably related, one of said members having bores therein contiguous to and spaced along said annular space, rollers rotatably mounted in said bores and extending therefrom through said annular space, said rollers and the other of said members having gear teeth in fluid-sealing meshing relation across the axial length of said annular space, vanes extending radially on said other of said members in spaced relation therearound and with each of said vanes having two oppositely disposed faces extending through said annular space and with each of said vanes having a radially outwardly disposed end surface in fluid-sealing relation with said one of said members, said rollers having a pocket interrupting said gear teeth on said rollers for receiving said vanes during the relative rotation of said members, said other of said members having a fluid inlet and a fluid outlet for the passage of fluid relative to said annular space, the improvement comprising two of said gear teeth on said roller being disposed adjacent said pocket for defining limits to said pocket, two convex arcuate surfaces on said roller and extending continuously radially inwardly from said two gear teeth for further defining limits to said pocket at opposite sides of said pocket, said two opposite faces of said vane being curvilinearly shaped and generated in conformance with rolling said roller over said vane and having said two convex arcuate surfaces simultaneously disposed on respective epicycloidal curves defining the entire vane curvilinearly-shaped faces, for rotation timing between said members when said vane is in said pocket so that relative rotation between said members is identical when said vane is in said pocket compared to when said gear teeth are in mesh.
 2. The subject matter of claim 1, wherein said gear teeth on said roller and one said other of said members are of a length equal to the axial length of said annular space.
 3. The subject matter of claim 1, wherein said gear teeth on said roller have a root circle along the radially inwardly disposed base of said gear teeth on said roller, and said two convex arcuate surfaces being located to have their respective centers on said root circle.
 4. The subject matter of claim 3, wherein the radius of the arcuate shape of each of said convex arcuate surfaces is equal to The width of said gear teeth along said root circle.
 5. The subject matter of claim 4, wherein the arc of each of said arcuate surfaces spans an angle of at least 30*.
 6. The subject matter of claim 1, wherein said roller has a fluid relief passageway in the surface defining said pocket and being spaced from said two gear teeth, for the relief of fluid pressure on said two opposite faces of said vane when said vane is in said pocket.
 7. The subject matter of claim 1, wherein said bores open onto said annular space with a dimension along said annular space less than the diameter of said roller, the spacing between two immediately adjacent ones of said vanes being such that the longest distance between said end surfaces of said vanes is greater than said dimension of said bores, to have two of said end surfaces respectively simultaneously disposed on opposite sides of said bores for fluid sealing with said one member across said bores, and each of said rollers having two spaced apart pockets for respectively receiving said vanes upon relative rotation of said members.
 8. The subject matter of claim 7, wherein said gear teeth between said two immediately adjacent said vanes have a fluid relief passageway extending across said gear teeth and into said two vanes for the relief of fluid pressure between said two vanes. 